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# UNIT 10: HEAT CAPACITY

• Heat capacity: It is the amount of heat energy required to raise the temperature of a body by 1 oC.

C = E / Δθ
Δθ represents the difference in temperature (θ
2 – θ1).

• Unit: J/oC.

• Specific heat capacity: It is the amount of heat energy required to raise the temperature of 1 kg of a substance by 1 oC.

c = E / (m Δθ)

• Unit: J/(kg oC)

• Specific heat capacity of different materials is different.

• For example, 1 kg of copper needs far less energy than 1 kg of water for a temperature rise of 1oC .

• Experiment to determine the specific heat capacity of a liquid:

• Use the formula: c = E / (m Δθ)

• Therefore,

• Calculate the electrical energy that changes into heat.

• Measure the mass of liquid.

• Note the initial and final temperatures.

• Precautions

• Use lagging for heat insulation.

• Stir liquid for uniform distribution of heat.

• After switching off the heater, allow mercury thread to rise and consider the maximum value to be the final reading.